This invention relates to a particle separating apparatus for separating a stock solution containing particles into a concentrated solution having a high content of particles and a clear solution having a low content of particles.
A known particle separating apparatus is disclosed in, for example, Japanese Unexamined Patent Publication No. 5-277402. This apparatus is provided with a stock solution supply passage for supplying a stock solution containing particles, a gas injector for injecting a gas into the stock solution in the supply passage while dispersing it, a particle separator, a concentrated solution discharge passage for discharging the concentrated solution in the particle separator, and a clear solution discharge passage for discharging the clear solution in the particle separator. The particle separator swirls the stock solution flown from the supply passage to create a static pressure difference in radial directions, moves gas particles in the stock solution toward the center by the static pressure difference to generate a gas-liquid mixed swirl at the center, and concentrates the particles at one end of the longitudinal direction of the swirl by this gas-liquid mixed swirl to thereby separate the stock solution into a clear solution and a concentrated solution.
According to a centrifugal force and the static pressure difference created by swirling the stock solution, the particles contained in the stock solution and having larger specific gravities than water are moved toward the outside of the swirl and discharged to the outside via the concentrated solution discharge passage provided at a lateral side, whereas the particles contained in the stock solution and having smaller specific gravities than water are moved toward the center and then moved upward together with air bubbles generated at the center to be discharged via the clear solution discharge passage provided at an upper side.
In the particle separating apparatus thus constructed, the particles having larger specific gravities than water and those having smaller specific gravities than water can be effectively separated. However, colloidal or gelatinous particles having specific gravities similar to that of water cannot be effectively separated. It is difficult to prevent these particles from being mixed into the clear solution and admitted into the clear solution discharge passage. Thus, this apparatus has a problem of being unable to sufficiently separate the particles if a large quantity of particles having specific gravities similar to that of water are contained in the stock solution.
In the particle separating apparatus disclosed in the above publication, an outer tube member forming an outer casing of the apparatus is provided. This outer tube member is comprised of a large-diameter portion located below for installing an inner tube member forming the particle separator and a small-diameter portion located above to be connected with an upper member where the concentrated solution discharge passage is provided. Thus, this apparatus has additional problems of the complicated construction of the outer tube member and difficulty to manufacture the outer tube member.
It is an object of the present invention to provide a particle separating apparatus which has overcome the problems residing in the prior art.
It is another object of the present invention to provide a particle separating apparatus which can effectively separate particles even if a large quantity of particles having specific gravities similar to that of water are contained in a stock solution, and has a simplified construction so as to be easily manufacturable.
According to an aspect of the invention, a particle separating apparatus is adapted for separating a stock solution containing particles into a concentrated solution having a high content of particles and a clear solution having a low content of particles. There are provided a stock solution supplier for supplying the stock solution into a main portion of the separating apparatus; a bubble generator for generating air bubbles to promote the separation of particles; a first separator for separating the stock solution into a first concentrated solution and a first clear solution according to a centrifugal force created by swirling the stock solution supplied from the stock solution supplier; a first discharge passage for discharging the first concentrated solution separated by the first separator to the outside; a filter provided inside the first separator for permitting the passage of the first clear solution and collecting the particles in the first clear solution; a second separator provided inside the filter for generating a gas-liquid mixed swirl of the air bubbles and the first clear solution at or near its center according to a static pressure difference created in its radial directions by swirling the first clear solution, and separating the first clear solution into a second concentrated solution and a second clear solution by the generated swirl; a second discharge passage for discharging the second concentrated solution separated by the second separator to the outside; and a clear solution guide passage for guiding the second clear solution to the outside.
According to another aspect of the invention, there are provided an outer tube formed of a tubular member; a pair of lids for closing openings at the opposite ends of the outer tube; an inner tube provided inside the outer tube and formed with through holes; a stock solution supplier for supplying the stock solution into a main portion of the separating apparatus in such a manner as to swirl the stock solution along the outer tube; a first discharge passage for discharging a first concentrated solution separated by a centrifugal force acting as the stock solution is swirled; a bubble generator for generating air bubbles to collect the particles in a first clear solution produced by separating the stock solution by the centrifugal force when the first clear solution is admitted into the inner tube through the through holes of the inner tube; a particle separating unit provided inside the inner tube for moving the air bubbles toward its center according to a static pressure difference created in its radial directions by swirling the first clear solution to generate a gas-liquid mixed swirl and concentrating the particles on one side of the longitudinal direction of the gas-liquid mixed swirl by the gas-liquid mixed swirl to separate the first clear solution into a second concentrated solution and a second clear solution; a second discharge passage for discharging the second concentrated solution separated by the particle separating unit to the outside; and a clear solution guide passage for guiding the second clear solution produced by removing the particles to the outside.
According to still another aspect of the invention, there are provided an outer tube formed of a tubular member; a pair of lids for closing openings at the opposite ends of the outer tube; a stock solution supplier for supplying the stock solution into the outer tube; a bubble generator for generating air bubbles to promote the separation of particles; a particle separating unit for moving the air bubbles toward its center according to a static pressure difference created in its radial directions by swirling the stock solution supplied from the stock solution supplier to generate a gas-liquid mixed swirl and concentrating the particles on one side of the longitudinal direction of the gas-liquid mixed swirl by the gas-liquid mixed swirl to separate the stock solution into a concentrated solution and a clear solution; a concentrated solution discharge passage for discharging the concentrated solution to the outside; and a clear solution guide passage for guiding the clear solution produced to the outside. The concentrated solution discharge passage and the stock solution supplier are connected with the outer tube in positions spaced apart along the longitudinal direction of the outer tube, and the outer diameter of the connected end of the stock solution supplier is set smaller than that of the connected end of the concentrated solution discharge passage.
According to yet still another aspect of the invention, there are provided an outer tube formed of a tubular member; a pair of lids for closing openings at the opposite ends of the outer tube; a stock solution supplier for supplying the stock solution into the outer tube; a bubble generator for generating air bubbles to promote the separation of particles; a particle separating unit for moving the air bubbles toward its center according to a static pressure difference created in its radial directions by swirling a stock solution supplied via the stock solution supply passage of the stock solution supplier to generate a gas-liquid mixed swirl and concentrating the particles on one side of the longitudinal direction of the gas-liquid mixed swirl by the gas-liquid mixed swirl to separate the stock solution into a concentrated solution and a clear solution; a concentrated solution discharge passage for discharging the concentrated solution to the outside; and a clear solution guide passage for guiding the clear solution produced to the outside. The circumferential surface of the outer tube is formed straight between a portion near where the stock solution supply passage is connected and a portion near where the concentrated solution discharge passage is connected.
According to further aspect of the invention, there are provided a stock solution supplier for supplying the stock solution into the separating apparatus; a foaming agent injector for injecting a foaming agent to promote the separation of particles; a particle separating unit for moving the air bubbles toward its center according to a static pressure difference created in its radial directions by swirling the stock solution supplied via a stock solution supply passage of the stock solution supplier to generate a gas-liquid mixed swirl and concentrating the particles on one side of the longitudinal direction of the gas-liquid mixed swirl by the gas-liquid mixed swirl to separate the stock solution into a concentrated solution and a clear solution; a concentrated solution discharge passage for discharging the concentrated solution to the outside; and a clear solution guide passage for guiding the clear solution produced to the outside.
These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawings.